Cloth-spreading machine

ABSTRACT

A cloth spreading machine. A spreading carriage is mounted to reciprocate to-and-fro along a spreading table. A support for a bale of cloth is carried by holding means mounted on the table, and a calender assembly is mounted on the carriage. The clothbale support is adjustable relatively to the carriage in a direction parallel to the direction of reciprocation of the carriage, as by a photocell responsive to changes of position of the vertical plane of the web of cloth hanging from the bale and passing between two pull-off rollers of the calender assembly.

United States Patent [191 Stumpf Dec. 18, 1973 1 CLOTH-SPREADING MACHINE[76] lnventor: Gunter Stumpf, 7421 Mehrstetten,

Kreis Munsingen, Germany [22] Filed: Oct. 12, 1971 [21] App]. No.:188,024

[30] Foreign Application Priority Data June 14, 1971 Germany P 21 29416.6

(52] U.S. C1 270/31, 226/20, 226/176,- 242/57, 242/58, 242/673 [51] Int.C1 B65h 29/46 [58] Field of Search 270/30, 31; 226/20, 226/176, 177;242/57, 57.1, 67.3, 58, 72

[56] References Cited UNITED STATES PATENTS 3,033,561 5/1962 Hanna270/31 2.175.823 10/193) Breth 270/31 957,588 5/1910 Weiss 270/313,181,859 5/1965 Sayles 270/31 FOREIGN PATENTS OR APPLICATIONS 1,554,3641/1969 France 270/86 Primary Examiner-Robert W. Michell AssistantExaminerL. R. Oremland Att0rneyRobert E. Wickersham et a1.

[57] ABSTRACT A cloth spreading machine. A spreading carriage is mountedto reciprocate to-and-fro along a spreading table. A support for a baleof cloth is carried by holding means mounted on the table, and acalender assembly is mounted on the carriage. The cloth-bale support isadjustable relatively to the carriage in a direction parallel to thedirection of reciprocation of the carriage, as by a photocell responsiveto changes of position of the 'vertical plane of the web of clothhanging from the bale and passing between two pull-off r01- lers of thecalender assembly.

13 Clalms, 5 Drawing Figures PATENTEUDEc 18 1915 SHEET 10F 3 INVENTORGUNTER STUMPF ATTORNEYS PATENTEUBEB 18 1915 3379541 sum 2 or 3 HINVENTOR GUNTER STUMPF ATTORNEYS minimum: 18 ms 3779541 SHEET 3 0F 3FIG. 3a

FIG. 3 b

k7 I m,

IN VEN TOR GUNTER STUMPF 0%., WM fiw ATTONEYS 1 CLOTH-SPREADING MACHINEBACKGROUND OF THE INVENTION The present invention relates to acloth-spreading machine.

In this machine, a spreading carriage is mounted to reciprocateto-and-fro along a spreading table, and a support for a bale of cloth iscarried by holding means mounted on the table. A calender assembly ismounted on the carriage and has two motor driven pull-off rollers and 'acutting device.

Prior art spreading machines, even fully automatic spreading machines,are quite capable of spreading out unfolded,,i.e. single-layer webs ofcloth; Such a machine begins at the right-hand end of the spreadingtable and lays out the web of cloth on the table free of tension, withthe edges accurately aligned. Shortly before reaching the end'of thelayer, it switches over to slow running, stops at the pre-set length andautomatically cuts off the web of fabric. The machine runs back againidling, switches over againto slow speed shortly before the beginning ofthe layer, stops, resumes feeding of the cloth web, and begins to spreadout the next layer. The necessary edge accuracy is guaranteed by lightbarriers which scan one or both edges of the web of cloth.

However, present day machines do have difficulties in laying out adoubled web,,i.e., a web folded down the middle to form a double layer.At certain positions in the known cloth-spreading machines, wherereversing rollers cause a change of the direction in which a web ofcloth extends as it is unwound from a bale of cloth, the sides of theweb of cloth which rest on each other in a doubled web become displaced,and this distorts the folded edge. Moreover, the relatively smalldiameter reversing roller mounted on the cutting-off means of knownspreading machines results in a kinking of the fold.

An object of the invention is to provide a clothspreading machine inwhich. the unwinding of the web of cloth is adversely affected by as fewas possible or by no reversing points at all between the bale of clothand the cutting means, and inwhich the aforesaiddisadvan- I tages areavoided.

SUMMARY OF THE INVENTION progressively decreases, the web extending fromit can be kept in a vertical plane. This important adjustability may beachieved by providing the cloth bale support with a pair of parallelhorizontal-support rods that are adjustable in the longitudinaldirection of the spreading table, and the means for adjusting the clothbale'support may be power driven. For example, the adjusting means maybe controlled by a photocell responsive to changes of position of theplane of the web of cloth between the bale and the pull-off rollers.

Further features and details of the invention will be apparent from theensuing description of one specific embodiment, given by way of example,with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a view in side elevation ofa spreading machine embodying the principles of the invention, lookingat the operating side;

FIG. 2 is a fragmentary view in perspective of the main parts of themachine of FIG. 1, and

FIGS. 3a, 3b and 3c are diagrammatic views in elevation of severalpossible positions of adjustment of the calender arrangement in themachine of FIGS. 1 and 2.

DESCRIPTION OF A PREFERRED EMBODIMENT The cloth-spreading machine shownin FIG. 1 has a stationary spreading table 1 with a table top 2.Extending along the front of the table 1, between its legs, is a roundrail 3. A spreading carriage 4 runs' on grooved rollers'S to reciprocateit. Along the rear of the table 1, the spreading carriage 4 may runon'ordinary wheels (not shown) on the longitudinal edge of the table top2. The carriag'e4 may be driven-by a direct current geared motor 6. Areceiving means 7 for a cloth bale is mounted on the carriage 4 so as tobe adjustable transversely to the length of. the table 1, and on each ofits side walls is a cloth bale support rod 8 to carry a bale 9 of cloth.I g

In this invention, these support rods 8 are, as explained below ingreater detail, adjustable longitudinally in a horizontal direction bymeans of a geared motor 41 (FIG. 2) located in the receiving means 7.The motor 41 receives control pulses from a photocell 10, the pulsesbeing emitted upon a change in distance between this photocell l0 and aweb 11 of cloth, due to the gradual change in the diameter of the bale9. The pulses are generated by a well-known type of capacitance circuit,there being a pair of spaced-apart plates in the feeler head, one plateat ground potential, while the other plate is at an oscillatingpotential determined by. the oscillations of the emitted light pulse. Alight barrier l2 provided beneath the photocell 10 serves, in the caseof poorly folded webs of cloth, to control their folded edge 13 (FIG. 2)and in the case of satisfactory folded webs of cloth to control theedges of the open sides.

On the spreading carriage 4, beneath the light barrier 12, are twomotor-driven calender pull-off rollers 14:; and 14b between which isdrawn the vertically hanging web 11 of cloth unwound from the cloth bale9, and of which the right-hand roller -14b is' horizontally adjustable.This adjustability is very important in the case of the folded material,since the fold edge of web of cloth wears more than the open edge.

It should also be mentioned that the bale 9 of cloth is rotated in aclockwise direction by a drive (known per se but not shown) which can bebrought into engagement with the periphery 9a (FIG. 2) of the bale 9, orwith the bale'shaft 38.

The vertically hanging web 11 of cloth, after passing through thecalender arrangement 14a and 14b, arrives in the region of a cut-offmeans 15 which, to allow for thickness of a stack of layers 16 locatedon the table top 2, can be adjusted in height by means of a handwheel17. 'The motor-driven rotary cutter 18' is mounted to move transverselyto the table top'2, to cut 't hrough the web 11 of fabric. The cuttingmeans 15 also includes a cutter guard 19 witha deflector plate 20mounted on it, to avoid wrinkles at the folded edge of the web 11 ofcloth which is to be spread.

On the front or operating side of the spreading carriage 4, at the topon the right, is an eccentric lever 22 connected to the front end of theshaft of the righthand calender pull-off roller 14b to adjust the latterhorizontally. A similar lever at the back (not shown) adjusts the rearend of the same shaft. Beneath the eccentric lever 22 is a control box23 containing switching and regulating means. On the left, beside thehandwheel 17, there is a slipping clutch 24 which in the main serves tosafeguard the machine in the event of heavy overload. It also comes intooperation when the machine is started, in that the slipping clutch 24gives constant acceleration of the machine from the state of rest up tomaximum spreading speed. Without such a clutch 24, the machine wouldstart abruptly, and the final speed would be achieved immediately.

FIG. 2 shows in perspective the essential parts of the apparatusaccording to the invention, from the righthand end face of the spreadingcarriage 4. Of the two panelled side parts of the spreading carriage 4,in which gearwheels, chain transmissions etc. are accommodated, only thefront part 27 is shown with its horizontal panelling 28 at the top andits right-hand vertical panelling 29.

The two side parts are connected to each other by round cross-struts, ofwhich only the cross-strut 30 is shown. On the left of it and at thesame height is a second cross-strut, not shown. The cloth bale holdingdevice 7 is mounted on these cross-struts 30 etc. by means of guiderollers 31 that are transversely adjustable. The rollers 31 are mountedon the underside of a rectangular-section frame 32. Counter rollers 33prevent tipping of the cloth bale holding device 7 when it is beingcharged with a cloth bale 9 and prevent displacement of the guiderollers 31 off the cross-struts 30 etc. for any other reason.

On some or all the inner faces of the frame 32, at least on the insidefaces of two narrow sides and of one broad side there are supportingwalls, e.g. the front supporting wall 34, these being reinforced at theupper end by a rectangular hollow section frame 35. Telescopicallyreceived in the open end of each of the front and rear sides of thehollow frame 35 is the cloth bale support rod 8 which is likewisepreferably rectangular in cross-section. The exposed end of each isprovided with a pillow 37 to receive one end of the shaft 8 of theclothbale. The opposite end of each supporting rod 8, located in thehollowprofile frame, is constructed as a rack 39. Inside the box formedby' the supporting walls are the two geared motors 41, driving pinions40 meshing with the rack part 39 of each supporting rod 8.

Both geared motors 41 receive their control pulses from the photocell10, and'the pulses are emitted when there is a change in the distancebetween the photocell l and the vertically hanging web 11 of cloth. Asthe radius of the cloth bale 9 becomes smaller, therefore, the pinions40 of the geared motors 41 start to rotate slowly, thereby advancing thesupporting rods 8, and thus also the cloth bale holding rod 38 with thebale 9 of cloth, to the right as viewed in FIG. 1. According to theinvention, this ensures that the web 11 of cloth always extends in aconstant vertical plane. Instead of being automatic, this control canalso be carried out by means of a handwheel, not shown.

Located underneath the photocell is the light barrier 12 which scans thefolded edge 13 of the web 11 of cloth. The light barrier 12 comprises asource of light and two opposed photo diodes having variable resistance,which is amplified toactuate a relay that actuates amotor control. Thezero condition of the light barrier 12 is achieved when one of thesediodes is illuminated and the other is darkened by the web of cloth. Ifboth diodes are illuminated or if both are darkened by the migration ofthe web of cloth, the web of cloth is adjusted toward the zero position.Both the light barrier 12 and the photocell 10 are mounted on a rod 42,which, to allow for different widths of cloth webs, is adjustable in abush 43 mounted on the front part 27.

The calender arrangement which then follows in the direction of movementof the web 11 of cloth comprises the previously mentioned calenderpull-off rollers 14a and 14b, which can be engaged and disengaged by apivot lever 45 and a coupling 44. The drive of both rollers may be bychains and sprockets mounted at the back and not shown, operatingsynchronously with the drive of the spreading carriage 4, i.e. the driveof the rollers 14a and 14b is coupled to the drive of the spreadingcarriage 4 through a chain.

Applied by adhesion on each calender pull-off roller 14a, 14b is a foamplastics material 46 which, by reason of its good adhesion, permits ofslip-free pull-off of the folded web 11 of cloth. This coating of foamplastics material 46 is shown only in connection with roller 14a,although it is preferably on both rollers.

The shaft ends of the horizontally-displaceable calender pull-off roller14b run in bearings 47 which are adjustable by hand on a rod 48 and canbe locked in the desired position by means of a recessed head screw.

The cut-off means 15 located beneath the calender pull-off roller 14a issecured at each end by a bracket to a plate 50 mounted on the spreadingcarriage 4. As already mentioned, the cut-off means 15 is verticallyadjustable by means of the handwheel 17. The danger of wrinkling thefolded edge 13 of doubled material downstream of the cutting-off means15 is reduced by the deflector plate 20 mounted on the cutter guard 19.The guard 19 has alongitudinal slot 19a in which the cutting edge of therotary cutter 18 travels, so that it serves as a cutter guard 19. Thecutter guard 19 is supported by stub shafts 19b'mounted at its ends andeach secured against rotation in a plate 51 carried by the cut-off means15. As the cloth web llis unwound from the bale 9 of cloth it interruptsa light barrier 21 located on the cut-off means 15.

On the front, above the control box 23, is a rotary handle 52' forcontrolling the speedof the spreading carriage 4 and for reversing itsdirection of movement. A protective box 53 may contain a potentiometerfor that purpose, and also a switch.

The possibilities of adjusting the calender arrangement 14a, 14b whichare envisaged in the case of the apparatus according to the inventionare illustrated in FIGS. 3a to 3c, where once again the bearing 47 andthe rod 48 which carries the bearing 47 are shown.

The rods 48 extend into the side parts of the spreading carriage 4formed by the walls 27, 28 and 29 and are operatively connected to thepivot lever 22 on each side of the spreading carriage 4.

In the case of an unfolded, in other words singlelayer, web 11 of cloth,the two calender pull-off rollers 14a and 14b could be located parallelas shown in FIG. 3a. However, when spreading a double web 11 of cloth,parallel rollers produce an undesirable ironing effect on the fold 13since the folded edge, according to the structure of the material, issubject of a few millimetres more stretch than the open side of the web11 of material.

In order to avoid this, the horizontally adjustable roller 14b isinclined either as shown in FIG. 3b on the operating side or as shown inFIG. 30 on the opposite side of the spreading carriage 4. In the firstcase, the light barrier 12 controls the edge of the fold, and in thesecond case it controls the open side of the web 11 of cloth. I

Instead of the otherwise conventional threading of the web 11 of clothinto the calendering arrangement by hand, automatic threading isprovided in the apparatus according to the invention.

An essential condition of this is a sufficiently great feed-in distancebetween the calender pull-off rollers 14a and 14b. This is achieved by amanual reversal of the eccentric lever '22, i.e. the holding rods ,48are extended by a definite amountwith the bearings 47 secured thereonand thus with the right-hand calender pull-off roller 14b.

Subsequently, by means of a known cloth bale drive, not shown, which canbe brought into engagement with the periphery 9a of the cloth bale 9 orwith the cloth bale shaft 38, the web 1 1 of cloth wound on to the bale9 of cloth, can be slackened by means of a known fan generating a streamof air on the periphery of the cloth bale 9 and unwound until such timeas the light barrier 21 is interrupted. Then the calender pull-offroller 14b is adjusted horizontally to the left, again by means of theeccentric lever 22, and brought to bear onthe web 11 of cloth, whereuponthe spreading process can be- To those skilled in the art to which thisinvention relates, many changesin construction and widely differingembodiments and applications of the invention will suggest themselveswithout departing from the spirit and scope of the invention. Thedisclosures and the description herein are purely illustrative and arenot intended to be in any sense limiting.

I claim: t

1. A cloth-spreading machine including in combination:

a spreading table,

a spreading carriage reciprocally mounted on said table to reciprocateto-and-fro lengthwise along said table,

support means carried by said carriage each end of a bale of cloth,

calender means mounted on said carriage generally vertically below saidsupport means and having two motor driven pull-off rollers between whicha web of cloth is pulled off said bale, and a cut-off device below saidpull-off rollers,

adjustment means for said support means for changing the position ofsaid support means relative to said carriage in a direction parallel tothe direction of reciprocation of said carriage, for keeping the web ofcloth' vertical between itstangentially leaving said bale and itspassing through said pull-off rollers, and 7 power means for drivingsaid adjustment means, and sensing means responsive to horizontalchanges in position lengthwise of said tableof the plane of said web,for activating said power means for moving said support means relativeto said pull-off rollers so as to keep said web vertical as said baleunwinds and gets narrower in diameter.

for supporting 2. A cloth-spreading machine as claimed in claim 1,having means for adjusting each end of the pull-off roller which bearson the outside of the web of cloth to adjust horizontally toward andaway from its companion roller, said means for adjusting comprising anaxial shaft for said pull-off roller, journals for said shaft at itsopposite ends, said journals being movable horizontally and in thlengthwise direction of said table, and a pair of manually operatedeccentric levers mounted on opposite sides of said carriage and securedto said journals for moving them in said lengthwise direction.

3. A cloth-spreading machine as claimed in claim 1 having as saidsensing means a photocell connected to said power means.

4. A "cloth-spreading machine as claimed in claim 1 in which saidsupport means includes a pair of parallel horizontal support rodsextending in and adjustable individually by said power-driven adjustmentmeans in the lengthwise direction of said spreading table, there being apair of said adjustment means and a corresponding pair of said powermeans, and

second sensing means adjustable to scan one edge of said cloth web andable to actuate each of said power means separately to prevent lateralcreep of said web in either direction.

5. A cloth spreading machine as claimed in claim 4 in which each saidsupport rod has a portion of its length telescopically guided in arectangular-section hollow guide'andhas at the other end a mounting forone end of a shaft forming part of said support means carrying the baleof cloth.

6. A cloth-spreading machine as claimed in claim 5 in which a part ofthe support rod is formed as a rack,

and a pinion for adjusting said rod, engaging said rack.

7. A cloth-spreading machine as claimed in claim 6 having as each saidpower means a geared motor for driving each said pinion, each said motorbeing located in said support means, and means for adjusting th positionof each said motor relatively to said carriage in a horizontal directiontransverse to the movement of said carriage.

8. Acloth-spreading machine as claimed in claim 5 in which said supportmeans includes a frame of rectangular section and, mounted on it, abox-shaped component having opposite walls which carry said hollowguides.

9. A cloth-spreading machine as claimed in claim 4 including, as saidsecond sensing means, light barrier means for scanning either the foldededge or the open side of a doubled web of cloth.

10. A cloth-spreading machine including in combination:

adjustment means for said support means for changing the position ofsaid support means relative to said carriage in a direction parallel tothe direction of reciprocation of said carriage,

a photocell responsive to horizontal changes of position lengthwise ofsaid table of the plane of a web of cloth hanging down from said baleand between said pull-off rollers, and

power means for driving said adjustment means, controlled by andactuated by said photocell.

11. The cloth-spreading machine of claim 10 wherein said calender meansis mounted generally vertically below said support means and saidphotocell so actuates and adjusts said adjustment means that the web ofcloth is kept vertical between said bale and said calender means eventhough the diameter of the bale decreases as cloth is pulled offtherefrom.

12. The cloth spreading machine of claim 10 having a horizontal rodmounted transversely on said carriage, said photocell being supported bysaid rod and being adjustable thereon.

13. A cloth-spreading machine including in combination:

a spreading table,

a spreading carriage reciprocatingly mounted on said table toreciprocate to-and-fro lengthwise along said table, support means foreach end of a bale of cloth carried by said carriage,

calender means mounted on said carriage and having two motor-drivenpull-off rollers and a cutoff device,

adjustment means for said support means for changing the position ofeach said support means relative to said carriage in a directionparallel to the direction of reciprocation of said carriage,

light barrier means for scanning either the folded edge or the open sideof a doubled web of cloth and for actuating one of said adjustment meansif the web shifts laterally to counteract said lateral shift,

a photocell responsive to horizontal changes of position lengthwise ofsaid table of the plane of a web of cloth hanging down from said baleand between said pull-off rollers,

a horizontal rod on which said photocell and said light barrier arelocated, said horizontal rod being displaceable in a bearing bushmounted on said carriage, and

power means for driving said adjustment means, controlled by andactuated by said photocell and said light barrier means.

10 i l' 1 l

1. A cloth-spreading machine including in combination: a spreadingtable, a spreading carriage reciprocally mounted on said table toreciprocate to-and-fro lengthwise along said table, support meanscarried by said carriage for supporting each end of a bale of cloth,calender means mounted on said carriage generally vertically below saidsupport means and having two motor driven pull-off rollers between whicha web of cloth is pulled off said bale, and a cut-off device below saidpull-off rollers, adjustment means for said support means for changingthe position of said support means relative to said carriage in adirection parallel to the direction of reciprocation of said carriage,for keeping the web of cloth vertical between its tangentially leavingsaid bale and its passing through said pull-off rollers, and power meansfor driving said adjustment means, and sensing means responsive tohorizontal changes in position lengthwise of said table of the plane ofsaid web, for activating said power means for moving said support meansrelative to said pull-off rollers so as to keep said web vertical assaid bale unwinds and gets narrower in diameter.
 2. A cloth-spreadingmachine as claimed in claim 1, having means for adjusting each end ofthe pull-off roller which bears on the outside of the web of cloth toadjust horizontally toward and away from its companion roller, saidmeans for adjusting comprising an axial shaft for said pull-off roller,journals for said shaft at its opposite ends, said journals beingmovable horizontally and in th lengthwise direction of said table, and apair of manually operated eccentric levers mounted on opposite sides ofsaid carriage and secured to said journals for moving them in saidlengthwise direction.
 3. A cloth-spreading machine as claimed in claim 1having as said sensing means a photocell connected to said power means.4. A cloth-spreading machine as claimed in claim 1 in which said supportmeans includes a pair of parallel horizontal support rods extending inand adjustable individually by said power-driven adjustment means in thelengthwise direction of said spreading table, there being a pair of saidadjustment means and a corresponding pair of said power means, andsecond sensing means adjustable to scan one edge of said cloth web andable to actuate each of said power means separately to prevent lateralcreep of said web in either direction.
 5. A cloth spreading machine asclaimed in claim 4 in which each said support rod has a portion of itslength telescopically guided in a rectangular-section hollow guide andhas at the other end a mounting for one end of a shaft forming part ofsaid support means carrying the bale of cloth.
 6. A cloth-spreadingmachine as claimed in claim 5 in which a part of the support rod isformed as a rack, and a pinion for adjusting said rod, engaging saidrack.
 7. A cloth-spreading machine as claimed in claim 6 having as eachsaid power means a geared motor for driving each said pinion, each saidmotor being located in said support meanS, and means for adjusting thposition of each said motor relatively to said carriage in a horizontaldirection transverse to the movement of said carriage.
 8. Acloth-spreading machine as claimed in claim 5 in which said supportmeans includes a frame of rectangular section and, mounted on it, abox-shaped component having opposite walls which carry said hollowguides.
 9. A cloth-spreading machine as claimed in claim 4 including, assaid second sensing means, light barrier means for scanning either thefolded edge or the open side of a doubled web of cloth.
 10. Acloth-spreading machine including in combination: a spreading table, aspreading carriage reciprocally mounted on said table to reciprocateto-and-fro lengthwise along said table, support means for a bale ofcloth carried by said carriage, calender means mounted on said carriageand having two motor driven pull-off rollers and a cut-off device,adjustment means for said support means for changing the position ofsaid support means relative to said carriage in a direction parallel tothe direction of reciprocation of said carriage, a photocell responsiveto horizontal changes of position lengthwise of said table of the planeof a web of cloth hanging down from said bale and between said pull-offrollers, and power means for driving said adjustment means, controlledby and actuated by said photocell.
 11. The cloth-spreading machine ofclaim 10 wherein said calender means is mounted generally verticallybelow said support means and said photocell so actuates and adjusts saidadjustment means that the web of cloth is kept vertical between saidbale and said calender means even though the diameter of the baledecreases as cloth is pulled off therefrom.
 12. The cloth spreadingmachine of claim 10 having a horizontal rod mounted transversely on saidcarriage, said photocell being supported by said rod and beingadjustable thereon.
 13. A cloth-spreading machine including incombination: a spreading table, a spreading carriage reciprocatinglymounted on said table to reciprocate to-and-fro lengthwise along saidtable, support means for each end of a bale of cloth carried by saidcarriage, calender means mounted on said carriage and having twomotor-driven pull-off rollers and a cut-off device, adjustment means forsaid support means for changing the position of each said support meansrelative to said carriage in a direction parallel to the direction ofreciprocation of said carriage, light barrier means for scanning eitherthe folded edge or the open side of a doubled web of cloth and foractuating one of said adjustment means if the web shifts laterally tocounteract said lateral shift, a photocell responsive to horizontalchanges of position lengthwise of said table of the plane of a web ofcloth hanging down from said bale and between said pull-off rollers, ahorizontal rod on which said photocell and said light barrier arelocated, said horizontal rod being displaceable in a bearing bushmounted on said carriage, and power means for driving said adjustmentmeans, controlled by and actuated by said photocell and said lightbarrier means.